There's a Courtyard Marriott a couple blocks away from campus (and on the VLS side of campus), the Vanderbilt Marriott on the western edge of campus, and Loews Vanderbilt across the street from northern campus. No real experience with any of them, but I know Loews is the most highly regarded and they all tend to fill up far in advance. As you move away from campus (beyond walking distance), pricing is much better... or so I'm told.